Apparatus for dispensing a vapor phase reactant to a reaction chamber and related methods

ABSTRACT

An apparatus for dispensing a vapor phase reactant to a reaction chamber is disclosed. The apparatus may include: a first chamber configured for holding a source chemical with a first fill level; and a second chamber configured for holding the source chemical with a second fill level and in fluid communication with the first chamber via a fluid channel below the first and second fill levels. The apparatus may also include: a second chamber inlet opening in fluid communication with a pressurizing gas feed provided with a flow controller configured for controlling a flow of a pressurizing gas in the second chamber to control the first fill level in the first chamber. Methods for dispensing a vapor phase reactant are also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/562,112, entitled “Apparatus for Dispensing a Vapor Phase Reactant toa Reaction Chamber and Related Methods” and filed on Sep. 22, 2017, thedisclosure of which is hereby incorporated herein for reference.

FIELD OF INVENTION

The present disclosure relates generally to an apparatus for dispensinga vapor phase reactant to a reaction chamber and particular an apparatusfor dispensing a highly stable flow of vapor phase reactant to areaction chamber for an extended period of time. The disclosure alsoincludes methods for dispensing a vapor phase reactant to a reactionchamber.

BACKGROUND OF THE DISCLOSURE

Semiconductor processing apparatus commonly use one or more vapor phasereactants, i.e., precursors, as source chemicals for performingsemiconductor substrate processes, such as, for example, depositionprocesses, cleaning processes and etching processes. The vapor phasereactants are generally stored in chemical bottles, also commonlyreferred to as chemical ampoules.

High volume semiconductor fabrication facilities may utilize a largevolume of vapor phase reactants resulting in the requirement to eitherregularly re-charge the chemical ampoules with additional precursor, oralternatively, frequently exchange the discharged chemical ampoules forfull chemical ampoules.

However, there are some forms of precursors which are not readilyadaptable for re-charge of the chemical ampoule, for example, aparticular precursor may be easily degraded or a particular precursormay become strongly attached to the inner surface of the chemicalampoule during the re-charge procedure. In addition, the exchange of thedischarged chemical ampoule for a full chemical ampoule may incurundesirable down time for the semiconductor processing apparatus and mayalso necessitate the need for safe storage of a large number of chemicalampoules. Therefore, there is a desire to limit the frequency ofchemical ampoule exchanges or chemical ampoule re-charges.

One fundamental method for reducing the frequency of chemical ampouleexchange or chemical ampoule re-charge is to increase the size of thechemical ampoule thereby allowing the chemical ampoule to store moresource chemical. However, chemical ampoules are commonly heated to bringthe source chemical up to an operational temperature and stable,repeatable semiconductor processing performance necessitates thetemperature gradient across the precursor stored in the chemical ampoulebe minimized. For example, a chemical ampoule may be heated by a form ofheater referred to as a belt heater, wherein the belt heater is wrappedaround and encloses the outer surface of the chemical ampoule. However,as the size of the chemical ampoule increases an increased proportion ofthe heat provided by the belt heater may be undesirably absorbed at theouter surface of the chemical ampoule, thereby producing an undesirablethermal gradient across the chemical ampoule and consequential adeterioration in semiconductor fabrication processes.

In addition to the problems associated with heating a larger chemicalampoule, chemical ampoule upsizing may result in additional processingissues. For example, deposition processes, such as, for example, atomiclayer deposition processes, may utilize one or more chemical ampoules asthe chemical source(s) for deposition of materials. It may be necessaryto perform a stabilization process, prior to running product substrates,in order to stabilize the vapor pressure of the precursor inside thechemical ampoule. This stabilization process may expend valuableprocessing time and may be referred to as “dummy time.” It has beenfound that as the volume of the chemical ampoule increases, the “dummytime” required to stabilize the vapor pressure of the precursor insidethe chemical ampoule also noticeably increases, thereby wasting costlyprocessing time as well as consuming valuable precursor.

A chemical ampoule may be connected to a source of one or more carriergases. The carrier gases are introduced into the chemical ampoule anddrawn over the exposed surface of the source chemical, i.e., theprecursor, held within the chemical ampoule. The resulting evaporationof the source chemical causes a vapor of the source chemical to becomeentrained in the carrier gas to thereby produce the vapor phase reactantwhich can be dispensed to a reaction chamber. It has been found that themaximum evaporation rate of the source chemical occurs directly belowthe carrier gas inlet, i.e., where the carrier gas flow is mostproximate to the source chemical. It has also been found that as thesource chemical is consumed the fill level of the source chemicalreduces, increasing the distance between the carrier gas inlet and theexposed surface of the source chemical. The increase in distance betweenthe carrier gas inlet and the exposed surface of the source chemical canresult in an unwanted variation in the vapor phase reactant flow outfrom the chemical ampoule to the reaction chamber. For example, as thesource chemical is consumed and the distance between the carrier gasinlet and the surface of the source chemical increases, the flow ofvapor phase reactant from the chemical ampoule to the reaction chambermay decrease, resulting in an undesirable variation in semiconductorprocessing conditions.

Accordingly, apparatus and methods are desirable for dispensing a highlystable flow of vapor phase reactant to a reaction chamber for anextended period of time from a high volume chemical ampoule.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

In some embodiments of the disclosure, an apparatus for dispensing avapor phase reactant to a reaction chamber is provided. The apparatusmay comprise: a first chamber configured for holding a source chemicalwith a first fill level; and a second chamber, configured for holding asource chemical with a second fill level in fluid communication with thefirst chamber via a fluid channel below the first and second filllevels. The apparatus may also comprise; a first chamber inlet openingin fluid communication with a carrier gas feed line configured forflowing a carrier gas into the first chamber to cause a vapor of thesource chemical to become entrained in the carrier gas to produce thevapor phase reactant. The apparatus may further comprise: a firstchamber outlet opening in fluid communication with a gas outlet line andconfigured for dispensing the vapor phase reactant from the firstchamber; and a second chamber inlet opening in fluid communication witha pressurizing gas feed line provided with a flow controller configuredfor controlling a flow of a pressurizing gas in the second chamber tocontrol the first fill level in the first chamber.

The embodiments of the disclosure may also provide methods fordispensing a vapor phase reactant to a reaction chamber. The methods mayinclude: providing a first chamber for holding a source chemical with afirst fill level, and providing a second chamber configured for holdingthe source chemical with a second fill level in fluid communication withthe first chamber via a fluid channel. The methods may also comprise:flowing a carrier gas into the first chamber through a first chamberinlet opening, wherein flowing the carrier gas into the first chambercauses a vapor of the source chemical to become entrained in the carriergas to produce the vapor phase reactant, and dispensing the vapor phasereactant from the first chamber via a first chamber outlet opening influid communication with an outlet gas line. The methods may furthercomprise: controlling the flow of a pressurizing gas into the secondchamber via a second chamber inlet opening to regulate the first filllevel to a substantially constant level.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of theinvention, the advantages of embodiments of the disclosure may be morereadily ascertained from the description of certain examples of theembodiments of the disclosure when read in conjunction with theaccompanying drawings, in which:

FIG. 1 is a schematic diagram of a chemical delivery apparatus fordispensing a vapor phase reactant to a reaction chamber according to theembodiments of the disclosure;

FIG. 2A is a three-dimensional schematic diagram of an alternativechemical delivery apparatus for dispensing a vapor phase reactant to areaction chamber according to the embodiments of the disclosure;

FIG. 2B is a cross-sectional schematic diagram of the alternativechemical delivery apparatus for dispensing a vapor phase reactant to areaction chamber according to the embodiments of the disclosure;

FIG. 3 is an exploded view of a temperature controlled chemicaldispensing apparatus according to the embodiments of the disclosure;

FIG. 4 illustrates an exemplary process flow for dispensing a vaporphase reactant to a reaction chamber according to the embodiments of thedisclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The illustrations presented herein are not meant to be actual views ofany particular material, structure, or device, but are merely idealizedrepresentations that are used to describe embodiments of the disclosure.

The embodiments of the disclosure may include apparatus and methods fordispensing a vapor phase reactant to a reaction chamber. In particular,the embodiments of the disclosure may include an apparatus capable ofdispensing a highly stable flow of vapor phase reactant to asemiconductor reaction chamber for an extended period of time.

The problems associated with the temperature gradient, i.e., thetemperature differential, across the volume of the source chemical heldwithin the dispensing apparatus may be alleviated by the employment oftwo or more independently controlled heating apparatus integrated intothe chemical dispensing apparatus. For example, the two or moreindependently controlled heating apparatus may be disposed at strategiclocations in the chemical dispensing apparatus. The two or moreindependently controlled heating apparatus therefore minimize thetemperature gradient across the volume of the source chemical andthereby provide a uniform form of vapor phase reactant to a reactionchamber.

In addition, the problems associated with undesirable precursorstabilization time and variation in vapor phase reactant flow over anextended period of time may be addressed by utilizing a two chamberchemical ampoule, wherein the two chambers are fluidly connected to oneanother. A pressure control unit may be associated with a pressurizinggas feed line into a second chamber such that a pressurizing gas mayintroduce a controlled pressure over the surface of the source chemicalin the second chamber. The controlled pressure over the source chemicalin the second chamber can thereby regulate the fill level in the secondchamber, i.e., the level of the exposed surface of source chemical.Since the first chamber is fluidly connected to a second chamber theability to control the fill level in a second chamber consequentiallyresults in the ability to control, i.e., regulate, the fill level in thefirst chamber. The two chamber chemical dispensing apparatus cantherefore substantially maintain the distance between the carrier gasinlet and the exposed surface of the source chemical, in the dispensingportion of the apparatus, resulting in a reduced stabilization time anda more stable vapor phase reactant flow over an extended period of time.

The embodiments of the disclosure may be understood in more detail withreference to FIG. 1 which illustrates a schematic diagram of a chemicaldelivery apparatus for dispensing a vapor phase reactant to a reactionchamber according to the embodiments of the disclosure. In more detail,the apparatus 100 for delivering a vapor phase reactant to a reactionchamber may comprise a first chamber 102 configured for holding a sourcechemical 104 and a second chamber 106 configured for holding a sourcechemical 104′. The first chamber 102 and the second chamber 106 may befluid communication with one another as a result of a fluid channel 108disposed between the first chamber 102 and the second chamber 106. Sincethe first chamber 102 and the second chamber 106 are in fluidcommunication with one another, the source chemical 104 and 104′disposed within the first chamber 102 and the second chamber 106 maycomprise a common source chemical, i.e., the source chemical in both thefirst chamber 102 and the second chamber 106 are identical.

In some embodiments of the disclosure, the first chamber 102 may bepartially separated from the second chamber 106 utilizing a channel 114disposed between the two chambers, the base of the channel 114 formingthe top surface of the fluid channel 108 and the common base of thefirst chamber 102 and the second chamber 106 forming the base of thefluid channel 108. In other embodiments, a physical barrier, such as,for example, a physical partition may be disposed partially between thefirst chamber 102 and the second chamber 106 whilst maintaining anunrestricted fluid channel between the two chambers.

In some embodiments of the disclosure, the source chemical 104 heldwithin the first chamber 102 may be filled up to a first fill level 110,i.e., the first fill level 110 indicates the level of the upper exposedsurface of the source chemical 104 disposed within the first chamber102. In some embodiments of the disclosure, the source chemical 104′held within the second chamber 106 may be filled up to a second filllevel 112, i.e., the second fill level 112 indicates the level of theupper exposed surface of the source chemical 104′ disposed within thesecond chamber 106. Under equilibrium conditions, the first fill level110 and the second fill level 112 are substantially equal, resultingfrom the fluid communication between the first chamber 102 and thesecond chamber 106, the fluid channel between the first chamber 102 andthe second chamber 106 being disposed beneath the first and second filllevels.

In some embodiments of the disclosure, the first fill level 110 and thesecond fill level may be monitored utilizing one or more liquid levelsensors. For example, a liquid level sensor 116 may be disposed withinthe first chamber 102 and may contact the source chemical 104 such thatthe position of the first fill level 110 within the first chamber 102may be monitored. In some embodiments, the dispensing apparatus 100 mayalso include an additional liquid level sensor 118 disposed within thesecond chamber 106 and may contact the source chemical 104′ such thatthe position of the second fill level 112 within the second chamber 106may also be monitored.

The dispensing apparatus 100 may also comprise a first chamber inletopening 120 in fluid communication with a carrier gas feed line 122. Inaddition, the carrier gas feed line 122 may include the valve 125 forcontrolling the flow of carrier gas into the first chamber 102. Thefirst chamber inlet opening 120 and the carrier gas feed line 122 may beconfigured for a flowing a carrier gas into the first chamber 102 abovethe first fill level 110 to cause a vapor of the source chemical 104 tobecome entrained in the carrier gas to produce the vapor phase reactant.

In some embodiments of the disclosure, the dispensing apparatus 100 mayalso comprise a first chamber outlet opening 124 in fluid communicationwith a gas outlet line 126 and configured for dispensing the vapor phasereactant out from the first chamber 102. In addition, the gas outletline 126 may include valve 128 for controlling the flow of vapor phasereactant out of the first chamber 102. The gas outlet line 126 may befed to the reaction chamber of a semiconductor processing apparatus,such that the vapor phase reactant dispensed from the first chamber 102may be utilized in a semiconductor fabrication process.

The dispensing apparatus 100 may also comprise a second chamber inletopening 130 in fluid communication with a pressurizing gas feed line132. In some embodiments of the disclosure, the pressurizing gas feedline 132 is configured for flowing a pressurizing gas above the secondfill level 112, the pressurizing gas configured to substantiallymaintain the level of the first fill level 110 in the first chamber 102.In addition, the pressurizing gas feed line 132 may include a pressurecontrol unit 134 disposed on the pressurizing gas feed line 132 andconfigured for controlling the pressure above the second fill level 112in the second chamber 106. In addition to the pressure control unit 134,the pressurizing gas feed line 132 may further comprise the valve 135for controlling the flow of the pressurizing gas in to the secondchamber 106.

In more detail, as a carrier gas (e.g., nitrogen or argon) is fed intocarrier gas feed line 122, the carrier gas flows into the volume abovethe first fill level 110 in the first chamber 102 and picks up vaporfrom the source chemical. The source chemical becomes entrained withinthe carrier gas to produce the vapor phase reactant which may bedispensed to a reaction chamber via gas outlet line 126. The process offlowing carrier gas, the carrier gas becoming entrained with the sourcechemical vapor and dispensing the vapor phase reactant out of the firstchamber via gas outlet line 126, causes the volume of source chemicalwithin the dispensing apparatus 100 to decrease and without anycorrective action the level of the first fill level (and consequentlythe level of the second fill level) will decrease below its originalposition. As previously stated, as the distance between the firstchamber inlet opening 120 and the first fill level 110 increases, theflow rate of the vapor phase precursor dispensed from the first chamber102 may also vary, i.e., may decrease, resulting in undesirable processvariation. In order to overcome the decrease in the level of the firstfill level 110, a pressurizing gas may be feed into the second chamber106 via pressurizing gas feed line 132. The pressurizing gas willcontrollably increase the pressure above the second fill level 112 inthe second chamber 106, utilizing pressure control unit 134, and theincrease in pressure will further decrease the second fill level 112 inthe second chamber 106. Since the second chamber 106 and the firstchamber 102 are in fluid communication with one another, via fluidchannel 108, any pressure induced decrease in the second fill level 112in the second chamber 106 will result in an increase in the level of thefirst fill level 110 in the first chamber 102. Hence any increase in thedistance between the first chamber inlet 120 and the first fill level110 can be compensated for by increasing the pressure over the sourcechemical in the second chamber 106.

As disclosed herein, the apparatus may include and utilize a chemicaldispensing apparatus comprising two fluidly connected chambers and apressurized gas feed line to substantially maintain the level of thefirst fill level in the first chamber. In addition to, or alternatively,the decrease in the level of the first fill level 110 due to theconsumption of the source chemical may be counteracted by the additionof further source chemical into dispensing apparatus 100, therebyreplenishing the source chemical as it is utilized and consequentlymaintaining the level of the first fill level 110. Therefore, in someembodiments of the disclosure, the dispensing apparatus 100 may furthercomprise an additional second chamber inlet opening 136 in fluidcommunication with a vapor feed line 138 configured for flowingadditional source chemical 104′ into the second chamber 106. Inaddition, the vapor feed line 138 may also comprise a valve 140 forcontrolling the flow of additional source chemical 104′ into the secondchamber 106.

In some embodiments of the disclosure, the additional source chemicalmay be feed into the first chamber 102 via an appropriate additionalinlet opening into the first chamber 102 (not shown). Therefore, eitherone or both of the first chamber and the second chamber may bereplenished with additional source chemical to maintain the level of thefirst fill level 110 in the first chamber 102.

An alternative configuration of the chemical dispensing apparatusaccording to the embodiments of the disclosure is illustrated in FIGS.2A and 2B, wherein FIG. 2A comprises a three-dimensional schematicdiagram of a chemical delivery apparatus and FIG. 2B illustrates across-sectional view of the same chemical delivery apparatus through theplane denoted by the A-A plane referenced in FIG. 2A. It should be notedthat the cross-sectional view illustrated in FIG. 2B represents thechemical delivery apparatus at the equilibrium position.

In more detail, the chemical dispensing apparatus 200 comprises a firstchamber 202, i.e., an inner chamber, configured for holding a sourcechemical up to a first fill level 210. The chemical dispensing apparatus200 also comprises a second chamber 206, i.e., an outer chamber,configured for holding a source chemical up to a second fill level 212.The first chamber 202 (inner chamber) and the second chamber 206 (outerchamber) are in fluid communication with one another via a fluid channel208.

In some embodiments of the disclosure, the first chamber 202 furthercomprises a first chamber inlet opening 220 in fluid communication witha carrier gas feed line 222 configured for flowing a carrier gas intothe first chamber 202 above the first fill level 210 to cause a vapor ofthe source chemical 204 to become entrained in the carrier gas toproduce the vapor phase reactant. An additional valve 225 may bedisposed on the carrier gas feed line 222 for providing further controlof the flow of the carrier gas into the first chamber 202 (see FIG. 2B).

In some embodiments of the disclosure, the first chamber 202 may alsocomprise a first chamber outlet 224 in fluid communication with a gasoutlet line 226 and configured for dispensing the vapor phase reactantout from the first chamber. Although not shown in FIGS. 2A and 2B, gasoutlet line 226 may extend out and be in fluid communication with areaction chamber of semiconductor processing apparatus, thereby allowinga vapor phase reactant to be dispensed to the reaction chamber. The gasoutlet line 226 may further comprise an additional valve 228 forproviding further control of the flow of the vapor phase reactant outfrom the first chamber 202 (see FIG. 2B).

The chemical dispensing apparatus of FIGS. 2A and 2B may also comprise asecond chamber inlet opening 230 in fluid communication with apressurizing gas feed line 234 configured for flowing a pressurizing gasabove the second fill level 212, the pressurizing gas configured tosubstantially maintain the level of the first fill level 210 in thefirst chamber 202, i.e., the inner chamber of FIGS. 2A and 2B.

To further control the pressure above the second fill level 212 in thesecond chamber 206, the chemical dispensing apparatus 200 may include apressure control unit 234 disposed on the pressurizing gas feed line232, the pressure control unit 234 configured to regulate the pressurein the second chamber 206 above the second fill level 212.

In some embodiments, the second chamber 206, i.e., the outer chamber,may further comprise a second chamber outlet opening 236 in fluidcommunication with a gas outlet line 238 configured for releasing atleast a portion of the pressurizing gas from the second chamber 204,i.e., releasing the pressurizing gas from the second chamber 206 via gasoutlet line 238 may be further utilized to control the pressure withinthe second chamber above the second fill level. Additional control ofthe pressure above the second fill level 212 within the second chamber206 may be provided by the valve 240 disposed on the gas outlet line 238(see FIG. 2B).

To further assist in the regulation of the level of the first fill level210 in the first chamber 202, the dispensing apparatus 200 may furthercomprise one or more liquid level sensors. For example, the datarecorded from the one or more liquid level sensors can be utilized in afeedback circuit to enable regulation of the pressure control unit 234disposed upon the pressurized gas feed line 232. As a non-limitingexample, a liquid level sensor 216 may be disposed within the firstchamber 202 and contacting the source chemical held 204 held with thefirst chamber 202. In additional embodiments of the disclosure, anadditional liquid level sensor 218 may be disposed within the secondchamber 206 and contacting the source chemical 204′ held with the secondchamber 206.

Although not shown in FIGS. 2A and 2B, the chemical dispensing apparatus200 may further comprise an additional inlet opening in one or both ofthe first chamber 202 and the second chamber 206, wherein the additionalinlet opening is in fluid communication with a vapor feed lineconfigured for flowing additional source chemical into one or both ofthe first chamber 202 and the second chamber 206. The ability tore-charge the source chemical with the chemical dispensing apparatus 200allows for further regulation of the level of the first fill level 210within the first chamber 202.

In some embodiments of the disclosure, the first chamber 202 maycomprise an inner cylinder. In some embodiments, the inner cylindercomprise a top wall, wherein the top wall comprises a number of openings220 and 224 configured for the inlet and outlet of gases and a furtheropening configured for the insertion of the liquid level sensor 216. Insome embodiments, the inner cylinder further comprises a sidewall and anopen base region, the open base region allowing fluid communication withthe second chamber 206 via fluid channel 208.

In some embodiments of the disclosure, the second chamber 206 maycomprise an outer partially hollow cylinder disposed concentric with andsurrounding the inner cylinder (see FIG. 2A). The second chamber 206,i.e., the outer cylinder, may be only partially hollow as a portion ofthe base region of the second chamber comprises the base of the fluidchannel 208 between the first chamber 202 and the second chamber 206.

In further embodiments of the disclosure, the chemical dispensingapparatus 200 comprises a channel 214 disposed between the innercylinder (the first chamber 202) and the outer cylinder (the secondchamber 204). The channel 214 may be circular in form and concentric tothe inner cylinder, although other configurations may be utilized. Thechannel 214 may extend from the top wall of the first chamber 204 downand adjacent to the side wall of the inner cylinder, terminating priorto the base of the apparatus, the base of the channel 214 comprising aportion of the top wall of the fluid channel 208 between the firstchamber 202 and the second chamber 206.

Embodiments of the disclosure may also comprise apparatus for heating achemical dispensing apparatus and particular apparatus for minimizingthe temperature gradient, i.e., the thermal differentiation, across thevolume of the source chemical held within the dispensing apparatus. Theembodiments of the disclosure may comprise apparatus for heating thechemical dispensing apparatus 200 of FIGS. 2A and 2B, although theapparatus described herein may be utilized to uniformly heatingalternative chemical dispensing apparatus.

In more detail and with reference to FIG. 3, a temperature controlledchemical dispensing apparatus 300 may comprise a first heating apparatus302, a second heating apparatus 304 and a chemical dispensing apparatus200. As described previously herein, the chemical dispensing apparatus200 may comprise a first chamber 202, i.e., the inner cylinder, and asecond chamber 206, i.e., the outer cylinder. Disposed between the firstchamber 202 and the second chamber 204 is a channel 214 which may becircular in form and concentric to the first chamber 202, the channel214 extending down from the top wall of the first chamber adjacent tothe side wall of the first chamber 202.

In some embodiments of the disclosure, the first heating apparatus 302may be placed within the channel 214 disposed between the inner cylinderand the outer cylinder. As a non-limiting example, the first heatingapparatus 302 may comprise a hollow cylinder with substantially the samediameter as the channel 214 disposed between the inner cylinder and theouter cylinder. Therefore, heating apparatus 302 may be inserted intothe channel 214 between the inner cylinder and the outer cylinder toprovide heating to both the inner cylinder (first chamber 202) and theouter cylinder (second chamber 204). As a non-limiting example, thefirst heating apparatus 302 may comprise a belt heater which may beconfigured for insertion into channel 214.

In some embodiments of the disclosure, a second heating apparatus 304may be utilized to provide further temperature control to the chemicaldispensing apparatus 200. The second heating apparatus 304 may comprisea hollow cylinder and may be disposed around the outer surface of theouter cylinder of chemical dispensing apparatus 200. For example, as anon-limiting example, the second heating apparatus 304 may comprise anadditional belt heater which is disposed around, i.e., wrapped around,and may be adjacent to the outer surface of the outer cylinder ofchemical dispensing apparatus 200.

In some embodiments of the disclosure, the first heating apparatus 302and the second heating apparatus 304 may be independently controlledsuch that the temperature gradient, i.e., the differential temperaturebetween the maximum temperature of the source chemical and the minimumtemperature of the source chemical, may be controlled within atemperature of less than 2° C., or less than 1° C., or even less than0.5° C. It should be noted that the temperature gradient of the sourcechemical may refer to the temperature gradient of the complete volume ofthe source chemical, i.e., both the source chemical held within thefirst chamber 202 and the source chemical held within the second chamber204. In alternative embodiments of the disclosure, the temperaturegradient of the source chemical may refer solely to the temperaturegradient of the source chemical held within the first chamber 202.

The embodiments of the disclosure may therefore comprise a high volumechemical dispensing apparatus capable of providing a stable flow ofvapor phase reactant for an extended period of time. For example, insome embodiment, the chemical dispensing apparatus may hold a totalvolume of source chemical greater than 1 liter, or greater than 2liters, or even greater than 4 liters. In some embodiments of thedisclosure, the chemical dispensing apparatus may be capable ofcontinuously dispensing a vapor phase reactant to a reaction chamber fora time period of greater than 200 hours, or greater than 300 hours, oreven greater than 400 hours. In some embodiments of the disclosure, thechemical dispensing apparatus of the disclosure may demonstrate areduced stabilization time, i.e., the time for the vapor pressure withinthe chemical dispensing apparatus to reach a steady-state value. Forexample, in the some embodiments, the vapor pressure of the sourcechemical within the chemical dispensing apparatus may reach asteady-state value after a time period of less than 500 seconds, or atime period of less than 300 seconds, or even a time period of than 100seconds.

The embodiments of the disclosure may also comprise methods fordispensing a vapor phase reactant to a reaction chamber. The methods ofthe disclosure may be further detailed with reference to FIG. 4 whichillustrates a process flow for a method 400 for dispensing a vapor phasereactant to a reaction chamber. In more detail, the method 400 maycomprise a process block 410 which comprises providing a first chamberfor holding a source chemical up to a first fill level. The firstchamber may comprise a portion of a chemical ampoule and may befabricated from corrosion resistant materials, such as, for example,quartz materials and stainless steel. The source chemical may comprise asolid (at room temperature) or a vapor and may be introduced into thefirst chamber utilizing a filling process such that the source chemicalmay fill the first chamber up to a first fill level, wherein the firstfill level may refer to the level of the upper exposed surface of thesource chemical within the first chamber.

The method 400 may continue with the process block 420, comprisingproviding a second chamber in fluid communication with the firstchamber. Again, the second chamber may comprise a portion of a chemicalampoule and may be fabricated from corrosion resistant materials, suchas, for example, quartz materials and stainless steel. Disposed betweenthe first chamber and the second chamber may be a fluid channel forproviding fluid communication between the first chamber and the secondchamber. In some embodiments of the disclosure, the second chamber maybe filled with the source chemical up to a second fill level, whereinthe second fill level may refer to the level of the upper exposedsurface of the source chemical within the second chamber. Since thefirst chamber and the second chamber are in fluid communication, theprocess of filling either of the first chamber or the second chamberwith source chemical will result in the filling of both chambers,provided the fluid channel between the two chambers is disposed at thebase of the first chamber and the second chamber. Again, since the firstchamber and the second chamber are in fluid communication the first filllevel and the second fill level are substantially equal underequilibrium conditions.

The method 400 may continue with process block 430, comprising flowing acarrier gas into the first chamber to produce the vapor phase reactant.In more detail, the first chamber may comprise an inlet opening in fluidcommunication with a carrier gas feed line. One or more carrier gases(e.g., nitrogen or argon) may be introduced into the first chamber viathe carrier gas feed line and may cause a vapor of the source chemicalto become entrained in the carrier gas thereby producing the vapor phasereactant. The consequence of producing the vapor phase reactant from thesource chemical vapor is that a portion of the source chemical heldwithin the first chamber is consumed. The consumption of the sourcechemical within the first chamber would normally result in a decline inthe level of the first fill level of the source chemical within thefirst chamber; however, as described herein the methods of thedisclosure counteract the decline in the first fill level within thefirst chamber.

The method 400 may continue with process block 440, comprisingdispensing the vapor phase reactant from the first chamber. In moredetail, the vapor phase reactant may be transported out of the firstchamber via a gas outlet line in fluid communication with the firstchamber. The transport of the vapor phase reactant out of the firstchamber, i.e., out of the chemical dispensing apparatus, may be achievedvia the flow of carrier into and out of the first chamber. In someembodiments, of the disclosure the gas outlet line from the firstchamber may be in fluid communication with a reaction chamber of asemiconductor processing apparatus, such that the vapor phase reactantmay be utilized in a semiconductor fabrication process.

The method 400 may continue with process block 450, comprisingcontrolling the pressure over the source chemical held within the secondchamber. In more detail, the pressure over the source chemical held withthe second chamber may be controlled by a pressure control unit and apressurizing gas line configured for flowing a pressurizing gas into thesecond chamber. The pressurizing gas may accumulate above the secondfill level of the source chemical within the second chamber and may alsoapply a downward pressure on the source chemical held with the secondchamber. The downward pressure may result in a decline in the secondfill level which will in turn result in an increase in the first filllevel in the first chamber due to the fact that the first chamber andthe second chamber are in fluid communication with one another.Therefore, controlling the pressure over the source chemical held withinthe second chamber directly controls the first fill level in the firstchamber. In some embodiments of the disclosure, the pressure over thesource chemical contained with the second chamber may be controlled viaa pressure control unit, a pressurizing gas line and a valve disposed onthe pressurizing gas line. In addition, the control of the pressure overthe source chemical contained within the second chamber may becontrolled via a gas outlet line which may be utilized to release aportion of the pressurizing gas out from the second chamber. Thereforein some embodiments, the method may comprise releasing at least aportion of the pressurizing gas from the second chamber via a secondchamber outlet opening.

The method 400 may continue with process block 460, comprisingregulating the first fill level at a substantially constant level. Inmore detail, the pressure over the source chemical in the second chambermay be controlled to directly regulate the level of the first fill levelin the first chamber. Therefore, as source chemical is consumed in thefirst chamber via the formation of the vapor phase reactant, thepressure over the source chemical in the second chamber may be increasedto regulate the first fill level at a substantially constant level. Tofurther enable the regulation of the first fill level at a substantiallyconstant level, one or more liquid level sensors may be utilized tomonitor the liquid level in the chemical dispensing apparatus andprovide a control signal for the pressure control unit associated withthe pressurizing gas line. Therefore, in some embodiments of thedisclosure, regulating the first fill level at a substantially constantlevel further comprises monitoring the first fill level in the firstchamber utilizing a liquid sensor. The liquid sensor may monitor adecrease in the level of the first fill level and provide a controlsignal to the pressure control unit to thereby increase the pressureover the source chemical in the second chamber thereby counteracting anychange in the level of the first fill level in the first chamber. Insome embodiments of the disclosure, an additional liquid level sensormay be disposed in the second chamber and in contact with the sourcechemical for monitoring the second fill level.

In addition to, or alternatively, the methods of the disclosure maycomprise regulating the first fill level at a substantially constantlevel by supplying additional source chemical to either the firstchamber or the second chamber. For example, one or more additional inletfeed lines may be associated with the first chamber and the secondchamber and the inlet feed line(s) may be utilized to introduceadditional source chemical into the chemical dispensing apparatus as thesource the chemical is consumed.

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention, which is defined by the appendedclaims and their legal equivalents. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the disclosure, in addition to those shown anddescribed herein, such as alternative useful combination of the elementsdescribed, may become apparent to those skilled in the art from thedescription. Such modifications and embodiments are also intended tofall within the scope of the appended claims.

What is claimed is:
 1. An apparatus for dispensing a vapor phasereactant to a reaction chamber, the apparatus comprising: a firstchamber configured for holding a source chemical with a first filllevel; a liquid level sensor for measuring the first fill level in thefirst chamber; a second chamber configured for holding the sourcechemical with a second fill level and in fluid communication with thefirst chamber via a fluid channel below the first and second filllevels; a first chamber inlet opening in fluid communication with acarrier gas feed line configured for flowing a carrier gas into thefirst chamber to cause a vapor of the source chemical to becomeentrained in the carrier gas to produce the vapor phase reactant; afirst chamber outlet opening in fluid communication with a gas outletline and configured for dispensing the vapor phase reactant from thefirst chamber; a second chamber inlet opening in fluid communicationwith a pressurizing gas feed line provided with a flow controllerconfigured for controlling a flow of a pressurizing gas in the secondchamber to control the first fill level in the first chamber; and acontrol unit operably connected to the liquid level sensor and the flowcontroller, wherein the control unit is programmed to control flow ofthe pressurizing gas into the second chamber via the flow controllerbased on an output of the liquid level sensor to regulate the first filllevel at a constant level.
 2. The apparatus of claim 1, wherein thecarrier gas feed line is configured for flowing the carrier gas into thefirst chamber above the first fill level.
 3. The apparatus of claim 1,further comprising a second chamber outlet opening in fluidcommunication with a gas outlet line configured to release at least aportion of the pressuring gas from the second chamber.
 4. The apparatusof claim 1, further comprising an additional liquid level sensordisposed within the second chamber and contacting the source chemical.5. The apparatus of claim 1, further comprising an additional secondchamber inlet opening in fluid communication with a vapor feed lineconfigured for flowing additional source chemical into the secondchamber.
 6. The apparatus of claim 1, wherein the first chambercomprises an inner cylinder and the second chamber comprises an outerpartially hollow cylinder disposed concentric with and surrounding theinner cylinder.
 7. The apparatus of claim 6, further comprising aheating apparatus disposed between the inner cylinder and the outercylinder.
 8. The apparatus of claim 1, further comprising a heatingapparatus disposed around the first chamber.
 9. The apparatus of claim1, further comprising a heating apparatus disposed around the secondchamber.
 10. The apparatus of claim 1, wherein a total volume of sourcechemical held within the first chamber and the second chamber is greaterthan 4 liters.
 11. The apparatus of claim 1, wherein a temperaturegradient across a total volume of the source chemical is less than 1° C.